1. Field of the Invention
The present invention generally relates to a pack frame and sack which is adapted to be utilized by campers, hunters, fishermen, climbers and the like and, more particularly, to those backpacks which utilize the hips of the user to support the load.
2. Prior Art
There are numerous pieces of prior art which disclose backpacks, pack frames and related apparatus. One of the most pertinent pieces of prior art discloses a pack frame and sack therefor which has a primary object to provide a pack frame by which a major portion of the load is carried by the hips of the user. In this device, the hip strap is padded and is tightened about the hips of the user in a position which is intended to engage the hip bones. The load carried by the sack is transferred to the hip strap at each side rather than primarily to the back or shoulders of the user. In this device, an L-shaped hip tube having an upright post and a forward extending arm is mounted adjacent the lower end of side bars and extends forwardly along the hip of the user. A joint for connecting each hip tube and the side bars is adjustable upwardly and downwardly along the side bar while a series of differently angled holes in the post of the hip tube permits the angle of the hip tube to be varied through the use of a removeable pin. The hip strap includes an outer strap and inner padding and is tightened about the hips of the user while a pin carried in each side of the hip strap extends through a grommet at the lower end of the corresponding shoulder strap and through the corresponding hip tube so that the weight of the pack is concentrated at the sides of the hips of the user rather than on the shoulder. The inadequacies of this device are obvious. Since the hip tubes are attached rigidly to the frame of the pack on one end, and to a single point on the belt at the other, that weight of the pack which is not being carried by the shoulders is brought to bear on a small area over each hip. Since the hips rise and fall in walking, friction occurs between the belt and the hip.
Another backpack and frame disclosed by the prior art utilizes a hip belt which is disposed about the waist of the wearer. The pack frame has two substantially vertical side bars and remaining sections of tubing and tees which form the side and transverse connectors of the frame. At least some of the joints of the tubing sections and tees are detachable so that the frame may be disassembled. The hip belt is disposed about the waist of the wearer and holds the bottom of the frame in a vertical position. The problem which arises by use of this device is apparent in its design. An attempt is made to support the load about the waist of the user, but there is no provision for support and independence between the load and the user.
Another pack frame and assembly which is disclosed by the prior art is adapted to be carried upon a person's back through the use of shoulder straps and having hip-engaing means thereon to bear on a portion of a person's hips so as to carry the majority of the load thereagainst. The hip-engaging means includes a backplate assembly having a pair of anchor plates connected to respective ones of the support tube members which constitute the primary vertical support of the pack. The belt assembly is adapted to be placed about the waist of the user above the hip line, the full weight of the pack frame being centered at the waist of the user on opposite sides thereof as well as the user's shoulders. As with the devices described hereinabove, the inability to provide independence of movement between the user and the load renders the prior design inadequate.
The present invention substantially resolves the problem which are inherent in the devices disclosed by the prior art. A contoured belt is adapted to be disposed about the waist of the user, the belt including downwardly extending load support panels which are adapted to be coupled to the load at a point which is substantially below the waist. A pair of lever arms are each pivotally coupled to the bottom section of one of the pack frame side members, the lever arms being parallel to one another. The lever arms are coupled to one another whereby movement of one lever arm about its pivotal coupling will permit an equal and opposite movement of the second lever arm about its pivotal coupling. The lever arms are respectively secured to the downwardly extending load support panel. The pack frame is substantially isolated from the movement of the lever arms. In this manner, the user will be permitted to have normal rotational hip action without being retarded by the load supported on the pack frame. The support of the load is at a point substantially below the waist of the user which provides for better distribution of the load to the hips, the non-rigid coupling between the lever arm and the frame providing for independence of movement between the user and the load.